Method and apparatus for treating stenosis or other constriction in a bodily conduit

ABSTRACT

An apparatus and method for treating an occlusion or constriction, such as a stenosis in a blood vessel or other conduit in the body, as well as an apparatus and method for treating a tumor or cancerous area occurring around a conduit or duct in the body. The apparatus includes a catheter provided with a ribbed balloon encircling a portion near its distal end. When inserted into the body over a guide wire and transported to the site of the stenosis, the balloon is inflated one or more times and, due to the ribbed balloon, blood perfuses around the catheter during the treatment. A radioactive source of material is inserted through the catheter to the site of the stenosis or cancer where it is maintained in position for a period of time to reduce the occurrence of re-stenosis or cancer. A guide wire provided with a removable core can be utilized to properly maneuver the catheter to the site of the stenosis or cancer.

This is a continuation-in-part of application Ser. No. 08/220,681, filedMar. 31, 1994, now U.S. Pat. No. 5,556,389, and application Ser. No.08/316,500, filed Sep. 30, 1994, now U.S. Pat. No. 5,618,266.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of treating a stenosis whichwould occur in various blood vessels and other bodily conduits as wellas to the field of angioplasty. Additionally, the present invention isdirected to the field of treating cancer which would occur in variousbody conduits or ducts, as well as to the field of brachytherapy.

2. Description of the Prior Art

Various techniques have been developed to treat many different conduitsin the body when these conduits have become reduced in size due to theexistence of a stenosis or have been completely occluded. Thesetechniques include introducing a deflated balloon catheter to the siteof the stenosis or occlusion, inflating the balloon one or more times toeliminate the size of the stenosis, deflating the balloon and thenremoving the balloon catheter from the treatment site.

With respect to the vascular pathways, angioplasty is used to open anartery or blood vessel in the region where the stenosis or the occlusionhas occurred. A typical angioplasty procedure consists of making a smallincision through the body and into a blood vessel and then maneuvering aguide wire through the vascular system to a point beyond the stenosis orocclusion. A hollow catheter with a deflatable balloon near its distalend is threaded over the guide wire and advanced to the point ofstenosis or occlusion. The balloon is then inflated and deflated severaltimes to widen the constricted area, and is then withdrawn from thebody.

Unfortunately, although the angioplasty procedure does markedly reducethe area of stenosis or occlusion, many patients exhibit a reoccurrenceof the stenosis within a few months of the original procedure.

Although the original stenosis occurs by means of the build up of plaqueover a relatively long period of time, experimentation has lead many tobelieve that the reoccurrence of the stenosis after the originalangioplasty procedure is unrelated to the cause of the originalstenosis. It is believed that the inflation of the balloon catheter usedin the angioplasty procedure or the placement of a stent in the area ofthe stenosis causes irritation to the blood vessel. This irritationproduces a mechanism of action called hyperplasia, inducing the innerlayer of the blood vessel cells to rapidly reproduce, thereby causingrestenosis. It has been proposed that if the blood vessel is irradiatedat the point of the stenosis with a radioactive dose, the mechanism thatcauses hyperplasia would be destroyed without harming the blood vesselitself.

During this procedure, it is important to precisely control the amountof radiation which is directed to the blood vessel wall, since too muchradiation could actually induce hyperplasia as well as destroying aportion of the blood vessel, making it possible for an aneurism orrupture to occur. U.S. Pat. 5,213,561 issued to Weinstein et al and U.S.Pat. No. 5,199,939 issued to Dake et al, as well as PCT ApplicationPCT/US92/07447 to Shefer et al, describe various methods and apparatusfor introducing radiation to the site of a stenosis to endeavor toprevent restenosis.

The Weinstein et al patent describes a method and apparatus forpreventing restenosis after angioplasty. A balloon catheter transportedby a conventional guide wire is delivered to the location of thestenosis. Particles or crystals of radioactive material are embedded ormounted on a tube provided inside the balloon catheter. A retractableradiation shielding sleeve is slidable along the tube to cover thesource of radioactive material. Upon completion of the angioplasty, theshielding sleeve is retracted and the area of the stenosis isirradiated. Although this apparatus does introduce radiation to thepoint of the stenosis, the retractable shielding surrounding the sourceof radioactive material makes this catheter bulky and unwieldy to use.In this regard, it is very doubtful that a catheter system this bulkywould fit into the smaller branches or vessels of the heart. It is alsodoubtful that a catheter this bulky and stiff could be maneuveredthrough the tighter bends and turns in many of the vessels.

An additional embodiment of the Weinstein et al patent illustrates astent which is made of or coated with a radioactive material such asiridium 192. Since the radioactive material is provided on the outersurface of the stent, it is very difficult to precisely administer theproper dosage of radiation to prevent hyperplasia without administeringa level of radiation which would actually induce hyperplasia or otherdeleterious effects to the blood vessel.

The PCT application illustrates a method and apparatus for restenosistreatment by applying a radioactive dose to the stenosed region afterreduction of the region by angioplasty or other means. As shown in FIG.4, an angioplasty balloon is expanded in the vicinity of a lesion siteand radioactive elements provided on the exterior surface of the balloonare forced into contact with the region. Therefore, similar to theWeinstein et al patent, the presence of the radioactive material on theexterior of the catheter would make it very difficult to apply theprecise amount of radiation to the region of interest. Additionally,both the PCT application as well as the patent to Weinstein describeballoon catheters which do not allow the blood within the vessel to flowduring inflation of the balloon.

The patent to Dake et al shows a radioactive catheter for preventingrestenosis after angioplasty. However, this patent merely indicates thatan elongated flexible catheter is transported to the area of theoriginal stenosis after a balloon catheter has been withdrawn, therebylengthening the time to administer the entire procedure.

SUMMARY OF THE INVENTION

These and other deficiencies of the prior art are addressed by thepresent invention which is directed to a method and apparatus fortreating the location of a stenosis in a blood vessel or other hollowconduit in the body by inflating and deflating a balloon catheter one ormore times. A source of radiation is then advanced through the catheterto the site of the stenosis, centered within the blood vessel, and thesite is then treated for a period of time with radiation. Once thetreatment is completed, both the radiation source and the ballooncatheter are withdrawn.

According to the teachings of the present invention, a radiopaque guidewire is inserted into the body through a small incision and is thenintroduced into a blood vessel or similar conduit. Once in place, acatheter having a ribbed balloon attached near the distal end thereof isthreaded over the guide wire and is also advanced to the location oftreatment. The interior of the catheter is provided with an elasticmembrane, one-way valve or other similar device for sealing the distalend of the catheter, but allowing the guide wire to pass therethrough.The guide wire is then removed and the ribbed balloon is inflated one ormore times to reduce the size of the stenosis, while allowing blood toflow around the site of the stenosis to greatly decrease the patient'srisk of a myocardial infarction or heart attack. A radioactive source isadvanced into position through the balloon catheter to the site of theoriginal stenosis. With the balloon inflated, the balloon catheter andthe radioactive source are correctly centered within the blood vessel toadminister a precise dose to the original area of the stenosis. After aperiod of time in which the original site of the stenosis is irradiatedfrom the radioactive source, both the radioactive source and the ballooncatheter are then removed from the blood vessel and the body of thepatient.

Contrast dye, helpful in locating the position of the catheter within abody vessel is injected therein by a conduit provided on the exteriorsurface of the catheter or through the guide wire itself, after the coreof the guide wire has been removed.

Another embodiment of the present invention would include a membrane orsheath which would be attached to the ribbed balloon to insure thatblood will be able to flow through the profusion channels between eachof the lobes by insuring that plaque or other material does not clogthese channels.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a side view of a ribbed balloon catheter according to thepresent invention;

FIG. 2 is a side view of a second embodiment of the ribbed ballooncatheter according to the present invention;

FIG. 3 is a transverse cross-sectional view of the ribbed ballooncatheter of the present invention taken along lines 3--3 of FIG. 2;

FIG. 4 is a longitudinal sectional view of the ribbed balloon catheterof the present invention showing the radioactive source within theballoon catheter;

FIG. 5 is a longitudinal sectional view of the present invention showingthe guide wire and the one-way valve;

FIGS. 6-9 are end views of the elastic membrane shown in FIG. 4 with orwithout the guide wire inserted therethrough;

FIG. 10 is a front view of the one-way valve shown in FIG. 5;

FIG. 11 is a side view of the one-way valve with the guide wire passingtherethrough;

FIG. 12 is a front view of the one-way valve showing the smaller openingbehind the flap;

FIG. 13 is a side view of a removable core guide wire inserted into thebody;

FIG. 14 is a side view of the guide wire shown in FIG. 13 after the corehas been removed;

FIG. 15 is a side view of the guide wire shown in FIG. 14 after aLuer-Lock has been attached thereto; and

FIG. 16 is a side view of a catheter for the treatment of cancer withina vessel, duct or airway according to yet another embodiment of thepresent invention;

FIG. 17 is a front view of the ribbed balloon catheter having a membranesurrounding the lobes of the balloon; and

FIG. 18 is a front view of the ribbed balloon catheter having a membraneconnecting adjoining lobes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Although the present invention can be used to treat blockages in manybody conduits, for ease of explanation, the present invention will bediscussed with respect to a stenosis provided in a blood vessel.

FIGS. 1, 2 and 3 illustrate the catheter 10 of the present inventionafter it has been inserted into the body and moved to the site of astenosis 30 in a blood vessel 26. The catheter itself consists of ahollow, generally cylindrical member 12 which is constructed from afairly flexible material such as polyethylene glycol so that it can beeasily maneuvered within the body and travel over a guide wire 16 whichwas initially maneuvered in the blood vessel to a position beyond theactual site of the stenosis. The interior of the catheter can be made ofor coated with a friction reducing material, such as TEFLON (PTFE) toaid in the passing of the guide wire and the radioactive sources to thetreatment site. The catheter itself is slightly tapered at its distalend 14 to facilitate movement through blood vessels or similar conduitsor ducts. Both the guide wire 16 and the catheter 12 should be ofsufficient length to travel to the site of occlusion or constriction invarious conduits and certainly should be long enough to reach the heart.A ribbed balloon 18 surrounds a portion of the outer surface of thecatheter 12 and contains a number of ribbed pleats. When these pleatsare inflated by a syringe 24 injecting air into a conduit 25 extendingalong the exterior surface of the catheter 12 to the balloon 18, thesize of the stenosis would be reduced as well as allowing the catheterto be properly centered when a radioactive source is introduced to theoriginal site of the stenosis.

A second syringe 22 is also attached to the catheter 12 for injectingcontrast dye into the blood vessel to aid in the proper location of thecatheter. This contrast dye would travel through a conduit 20 alsoprovided on the exterior surface of the catheter to a site 28 near theproximal end of the balloon 18 (see FIG. 1) or could extend to a point32 beyond the distal end of the balloon 18 (see FIG. 2).

Alternatively, contrast dye can be introduced to the site of thestenosis by injecting the contrast dye directly into the interior of thecatheter 12. This is accomplished utilizing a guide wire provided with aremovable core, the operation of which will be subsequently explained.

Since the ribbed balloon 18 would inflate in a symmetrical pattern,blood would be allowed to profuse at various locations 34 during boththe angioplasty procedure as well as the radiation treatment. This flowof blood would greatly decrease the incidence of a myocardial infarctionor a heart attack and would allow the angioplasty procedure as well asthe radiation treatment to be performed as long as needed withoutcompletely blocking the flow of blood through the vessel. As shown inthe drawings, the ribbed balloon is provided with a number ofsymmetrical lobes which extend for the entire length of the balloon.Each of the lobes is provided with a constant diameter for substantiallyits entire length.

Since the catheter of the present invention would act as a conduit toallow a radiation source to be introduced to the site of the originalstenosis, it is important that the catheter should be sealed at a pointproximate to its distal end, while allowing a guide wire to exit thedistal end of the catheter 12. Consequently, the present inventionutilizes an elastic membrane 40 shown in FIGS. 4, and 6-9 to performthis function. This membrane can be constructed of any biocompatiblematerial 44 that will expand large enough to allow the guide wire 16 topass therethrough and then contract to form a closed seal when the guidewire is removed.

FIG. 6 illustrates the elastic membrane which is completely sealed priorto the guide wire passing through this membrane. FIG. 7 illustrates themembrane with a small hole 46 forming in the middle thereof which wouldallow the guide wire to pass therethrough as shown in FIG. 8. FIG. 9illustrates the elastic membrane 40 immediately after the guide wire 16has been removed.

As shown in FIG. 4, more than one elastic membrane 40 can be utilized toinsure that the catheter is sealed after the guide wire 16 is removed.Regardless of whether a single membrane or a plurality of membranes areused, the membrane is placed in the interior of the catheter 12 at alocation beyond the ribbed balloon 18, in such a manner as toeffectively seal the catheter from the blood vessel. Filters 42 can beprovided between each of these membranes for wiping the guide wire as ittravels through the balloon catheter 12. Because the guide wire 16extends into the blood vessel, and is then removed from the catheter 12after the catheter has been maneuvered to the correct location, it isimportant that blood or other liquids not be introduced into the sealedportion of the catheter since this would inhibit the proper placement ofthe radioactive source. The filtered material 42 can be constructed fromany biocompatible material that freely allows the guide wire 16 to passtherethrough as well as wiping the guide wire as it is withdrawn fromthe catheter 12. Cotton or angel foam have been found to be particularlyefficacious for this purpose.

An alternative embodiment in which a one-way valve 48 is used with, orin place of the elastic membrane 40 is shown in FIGS. 5, 10, 11 and 12.The one-way valve 48 is placed in the interior of the catheter beyondthe ribbed balloon 18. The one-way valve is provided with a relativelylarge flap 50 which is considerably larger than the hole 54 which itcovers. A tension hinge 52 insures that the flap remains in the closedposition during the absence of the guide wire 16. In use, as shown inFIG. 5, the guide wire 16 advances in the direction shown by arrow 56and the catheter advances in the direction shown by arrow 58. In thisinstance, as the guide wire passes through the relatively small hole 54,it pushes against the flap, causing the flap to rise and allow passageof the guide wire therethrough. As illustrated in FIG. 5, since the hole54 is much smaller than the size of the flap 50, the flap can only movein the clockwise direction and not in the counterclockwise direction. A"funnel-shaped" entry port 52 assists in allowing the guide wire 16 topass through the hole 54. If the one-way valve is used in conjunctionwith at least one of the elastic membranes 40 shown in FIG. 4, filtermaterial 42 can be provided between these two sealing members.

FIGS. 13-15 demonstrate a removable core guide wire 64 which can be usedinstead of the guide wire 16 illustrated in FIGS. 1 and 2. The guidewire 64 is provided with a flexible outer housing 58 which can beconstructed from such a material as nitinol. The removable core guide isprovided within the outer housing 58 and includes a soft, flexible,rounded tapered end leader 54 extending beyond one end 61 of the outerhousing 58. A slightly oversized cap 56 is provided over the second end63 of the outer housing 58 to allow the removable core to be removedfrom the outer housing with the guide wire has been properly positionedwithin the blood vessel. Once the core is removed, the guide wire wouldonly include the hollow outer housing 58 as well as a series of externalthreads 60 on the end of the guide wire extending out of the patient'sbody. This threading would allow a Luer-Lock 62 or similar device to bescrewed onto the outer housing 58 so that a syringe can inject contrastdye into the catheter. The removable core can be constructed fromTeflon, nitinol or any springy, soft biocompatible material. If theremovable guide wire as illustrated in FIGS. 13-15 is employed, theconduit 20 shown in FIGS. 1 and 2 used to deliver contrast dye to thevicinity of the stenosis is not needed.

The balloon catheter of the present invention as described can beutilized in the following manner to treat a stenosis as well as toprevent reoccurrence of the stenosis. Once the site of a stenosis isdetermined by appropriate diagnostic procedures, a small incision ismade in the body and, assuming that an angioplasty procedure isnecessitated, into a vessel. The guide wire 16 is then maneuvered intothe vascular pathway and is imaged under fluoroscopy while beingadvanced through the blood vessel pass the area of stenosis. Thecatheter 12, with the balloon 18 being deflated, is threaded over theguide wire 16 and it is also advanced such that the balloon 18 ismaneuvered to the area of the stenosis. Contrast dye is injected eitherthrough the external ports 28, 32 or the specially designed removablecore guide wire illustrated in FIGS. 13, 14 and 15. The contrast dyeenters the vascular pathway causing the blood vessel to becometemporarily opaque and allowing it to be imaged under fluoroscopy.

Since the contrast media is quickly absorbed by the body, multipleinjections of contrast dye are possible. An opaque marker can be appliedto one or both ends of the ribbed balloon 18 allowing it to be imagedunder fluoroscopy. Once the ribbed balloon is verified to be inposition, the balloon is inflated, the guide wire is withdrawn from thebody, and the angioplasty procedure commences.

At this point, the balloon 18 is inflated and deflated one or more timesto widen the constricted area. When the balloon is deflated, contrastdye can be injected again to verify the widening of the priorconstricted area. The balloon is then inflated to hold the catheter inplace for the radioactive treatment.

One or more radioactive sources 38 are provided on, or inside the distalend of a flexible member 36 which is advanced through the interior ofthe catheter 12 until it reaches the proper location (see FIG. 4). Theradioactive source treats the area of the original stenosis for aspecific period of time. The time that the source remains inside thecatheter depends upon the strength of the radioactive source and thedistance between the source and the inner blood vessel walls. Examplesof gamma type radiation sources which can be utilized in this procedurewould be cesium 137, cobalt 60, iodine 125, iodine 131, cobalt 57,iridium 192, gold 198, palladium 103, etc. Typically, treatment timescould last between approximately four minutes to approximately thirtyminutes or longer. Since iridium 192 has a well-defined energy levelwith a strength of 1-2 Curies, it is particularly well-suited to treatthe area of the original stenosis at the prescribed distance. In thisinstance, treatment times would be in the range of 5 to 10 minutes.After treatment with the radiation source has been completed, both theradiation-source and the catheter, with the balloon deflated, are thenremoved from the body.

Since the radiation source can have a deleterious effect on the body ifit is not precisely positioned with respect to the area of treatment,the present invention insures that the radiation source is positioned inthe center of the vessel at a predetermined distance from the area oftreatment. This is accomplished by inflating the ribbed balloon 18 whenthe radiation source is delivered to the proper location. Additionally,for safe measure, the balloon 18 can be inflated at all times when theradiation source is being delivered to the site of the treatment. Thepositioning of the radiation source with respect to the area oftreatment is crucial since next to the radiation source, it is possibleto receive thousands of Rads or centiGrays, units of measurement ofradiation dose. This dosage would drop to only a few hundred Rads orcentiGrays approximately 10 millimeters away from the source.

Although the present invention has been explained with respect to anangioplasty procedure, it is noted that this treatment could beconducted in virtually any conduit of the body with or without theinclusion of radiation treatment. This catheter can also be used totreat cancer in various areas of the body, such as the common bile duct,the bladder, the liver, the lungs, etc. employing the same ballooncatheter shown in FIGS. 1-15.

There are many instances in the body where cancer invades around andinto a vessel or airway. Treating and controlling the invasion of thecancer is difficult since a sealed prior art catheter having a removablebackbone wire on its inside was used to try to access the cancerousarea. Since the hollow duct of a vessel or other conduit includes manyturns and bend inside the body, the cancerous area could not be reacheddue to the stiffness of the catheter and the fact that the backbone wirewas unable to negotiate the turns. If the backbone wire was removed, thecatheter would bunch up and advancement would not be possible. Theballoon catheter of the present invention avoids these problems since aflexible guide wire is easily maneuvered into position and theclosed-end catheter is advanced over this guide wire giving access tothe cancerous area.

With this in mind, the following procedure can be utilized to treat acancerous area with radiation utilizing the catheter, guide wire andsealing means illustrated in FIGS. 1-15: The radiopaque guide wire 16 ismaneuvered into position either through a body orifice leading into thehollow duct or an opening created into the hollow duct by means of asmall incision or puncture. The radiopaque nature of this guide wireallows X-rays to be used to properly position the guide wire beyond thetumor or cancerous site, which in many ways, is similar in appearance tothe stenosis 30 of FIG. 1. The catheter system 10 is then threaded overthe guide wire 16 and advanced into position. A radioptic marking on theribbed balloon 18 makes it easy to position the catheter utilizingX-rays. To further confirm position of the catheter, a contrast dye maybe injected through either of the external ports 28, 32 or through theremovable guide wire illustrated in FIGS. 13-15. The balloon catheter isthen inflated and the guide wire is removed. The inflation of theballoon is especially valuable if the tumor has invaded the duct or iscausing extrinsic compression from outside the duct. This inflation willgive temporary relief from the constriction, allowing greater passing ofbodily fluids. A radioactive source or sources 38 contained on the endor inside the end of the flexible drive member 36 (FIG. 4) is advancedinside the catheter to align with the tumor or cancerous area. After aspecified time, the radiation and catheter are removed from the body.

The catheter apparatus including the flexible membrane or the one-wayvalve is very important since, once the guide wire is removed, thesystem becomes closed, thereby not allowing the radioactive source orsources to advance out the end of a catheter and into the body if theybecome detached from the drive member 36. Furthermore, similar to thepreviously described embodiments, the inflated ribbed balloon allowsbody fluids to pass around the catheter. For example, when treating thebile duct, the catheter does not allow passage of the bile,cholecystitis can develop due to the back up of bile into the liver andcause liver dysfunction. Additionally, when treating the airway of thelung, if the catheter does not allow mucus or air to pass, atelectasis(collapsing of the lobe or the lung) or obstructive pneumonia candevelop. This is a very harmful situation to the patient since thepatient's lung capacity has already been compromised due to the presenceof the cancer.

Similar to the previously described embodiments, the use of the inflatedballoon catheter 18 is helpful in centering the radioactive source orsources inside the hollow duct. Since radiation emission observes theinverse square law, it is quite important that the radioactive source beproperly centered because in areas of the body where the walls of thevessels are extremely radiosensitive, such as the bile duct, great harmcan be caused to the patient if the source is not centered and kept fromthe vessel wall. Too much radiation for a period of time in an areaproximate to the vessel wall can cause severe hemorrhaging or radiationnecrosis.

FIG. 16 illustrates a catheter and guide wire combination previouslydescribed, with the exception that a ribbed balloon or other means doesnot surround a portion of the exterior surface of the catheter. Thiscatheter system is important since, in instances where a cancerous site70 has invaded the vessel or duct wall 72 to a great extent, it would bevery difficult if not impossible to maneuver a catheter having a ribbedballoon to the cancerous site. Once the guide wire 16 is removed, theradioactive source or sources is maneuvered in place in a manner similarto the above-described procedures relating to the treatment of stenosisor cancer.

FIGS. 17 and 18 illustrate another embodiment of the present inventionin which a membrane or sheath is used to achieve a greater dilationeffect while allowing for a better blood profusion and the centering ofthe treatment source. Since plaque or other bodily material can plug thelongitudinal grooves or profusion channels between adjacent lobes of theribbed balloon, it is important that the channels or grooves definedbetween each of the lobes remain free of this material to allow bodilyfluid, such as blood, to pass freely between these grooves or channels.This is especially true during an angioplasty procedure.

The present invention overcomes the problem of the prior art byattaching a membrane or sheath 70 which would surround the entire ribbedballoon including lobes 71, 72, 73 and 74. This membrane or sheath 70would extend for either the entire length of the balloon or for aportion of the length of the balloon. Once the balloon is inflated, themembrane of sheath would be pulled tight between the gaps of the balloonlobes as the lobes are inflated.

This particular configuration would result in a greater dilation effectsince plaque or other bodily material cannot enter the gap spaces and isforced to move away from the membrane and lobes as expansion takes placedue to the inflation of the balloon lobes. Additionally, a longitudinalgrooves or profusion channels are maintained open and bodily fluids willflow freely, since no bodily plaque material can enter the gap spaces toplug or create a damming effect.

The membrane can be constructed from a non-elastic or a non-stretchingtype of material so a thick overall diameter is achieved when theballoon lobes are inflated. Alternatively, the membrane can also beconstructed out of an elastic or stretching type of material so thatwhen the balloon lobes are deflated, the membrane will recoil to itsoriginal shape and it is guaranteed the balloon lobes will compress toas small of a diameter as possible around the catheter tubing 12. Thiscompression would allow for the balloon catheter when it's in itsdeflated state to pass through tiny constricted spaces. A stretchablemembrane also allows for a thick diameter as long as the membrane cannotbe stretched beyond the desired diameter of the inflated lobes.

Alternatively, FIG. 18 illustrates a membrane or sheath which does notsurround all of the lobes of the balloon but merely is provided betweenthe lobes. For example, membrane portion 78 is provided between lobes 72and 74; membrane portion 80 is provided between lobes 74 and 86;membrane portion 84 is provided between lobes 86 and 88; and membraneportion 76 is provided between lobes 72 and 88. Similar to theembodiment illustrated with respect to FIG. 17, this membrane can beconstructed from a non-elastic or an elastic material. Furthermore, thismembrane portion may cover the entire length of the ribbed balloon or aportion of the length of the balloon.

Although preferred forms of the present invention have been hereindisclosed, it is to be understood that the present disclosure is made byway of example and that variation of posture without departing from thescope of the hereinafter claimed subject matter.

What is claimed is:
 1. A device for treating an occlusion or aconstriction in a vessel or other conduit in the body, comprising:aflexible, elongated, hollow catheter having a distal end and a proximalend; an inflatable ribbed balloon encircling a portion of said catheterproximate to said distal end, said ribbed balloon forming at least onepair of lobes defining longitudinal perfusion grooves between saidlobes, said grooves allowing liquid to flow around said at least onepair of lobes through said longitudinal grooves when said ribbed balloonis inflated; and a discontinuous membrane covering at least a portion ofsaid longitudinal grooves and affixed between said at least one pair ofsaid lobes.
 2. The device for treating an occlusion or a constriction ina vessel or other conduit in the body in accordance with claim 1,wherein said membrane covers the entire length of said ribbed balloon.3. A device for treating an occlusion or a constriction in a vessel orother conduit in the body, comprising:a flexible, elongated, hollowcatheter having a distal end a proximal end; an inflatable ribbedballoon encircling a portion of said catheter proximate to said distalend said ribbed balloon forming lobes defining longitudinal perfusiongrooves between said lobes when inflated, said grooves allowing liquidto flow around said lobes through said longitudinal grooves when saidribbed balloon is inflated; and a non-elastic membrane covering saidribbed balloon and said longitudinal grooves.
 4. The device for treatingan occlusion or a constriction in a vessel or other conduit in the bodyin accordance with claim 3, wherein said non-elastic membrane extendsfor the entire length of said ribbed balloon.
 5. The device for treatingan occlusion or a constriction in a vessel or other conduit in the bodyin accordance with claim 1, further comprising:an elongated, flexiblemember having a proximal end and a distal end, said distal end of saidflexible member provided with at least one radioactive source insertablewithin the hollow catheter and maneuverable to the site of the occlusionor constriction after said ribbed balloon has been inflated at leastonce, said at least one radioactive source centered with respect to thevessel or other conduit.
 6. The device for treating an occlusion or aconstriction in a vessel or other conduit in the body in accordance withclaim 5, wherein said radioactive source emits gamma type radiation. 7.The device for treating an occlusion or a constriction in a vessel orother conduit in the body in accordance with claim 5, wherein saidradioactive source is cesium 137, cobalt 60, iodine 125, iodine 131,cobalt 57, iridium 192, gold 198, palladium 103, strontium 89, strontium90, phosphate 32, or yttrium
 90. 8. The device for treating an occlusionor a constriction in a vessel or other conduit in the body in accordancewith claim 1, wherein the interior surface of said catheter is coatedwith a friction reducing material.
 9. The device for treating anocclusion or a constriction in a vessel or other conduit in the body inaccordance with claim 1, wherein the discontinuous membrane isnon-elastic.
 10. The device for treating an occlusion or a constrictionin a vessel or other conduit in the body in accordance with claim 3,further comprising:an elongated, flexible member having a proximal endand a distal end, said distal end of said flexible member provided withat least one radioactive source insertable within the hollow catheterand maneuverable to the site of the occlusion or constriction after saidribbed balloon has been inflated at least once, said at least oneradioactive source centered with respect to the vessel or other conduit.11. The device for treating an occlusion or a constriction in a vesselor other conduit in the body in accordance with claim 10, wherein saidradioactive source emits gamma type radiation.
 12. The device fortreating an occlusion or a constriction in a vessel or other conduit inthe body in accordance with claim 10, wherein said radioactive source iscesium 137, cobalt 60, iodine 125, iodine 131, cobalt 57, iridium 192,gold 198, palladium 103, strontium 89, strontium 90, phosphate 32, oryttrium
 90. 13. The device for treating an occlusion or a constrictionin a vessel or other conduit in the body in accordance with claim 3,wherein the interior surface of said catheter is coated with a frictionreducing material.